Types of Bifocal Contact Lenses

Bifocal contact lenses are lenses designed to correct vision for individuals who have a condition known as presbyopia. Presbyopia often develops with age and reduces one's ability to focus at different distances. Today's bifocal contacts are available in soft and rigid (gas permeable) materials. Bifocal lenses are also referred to as "multifocal" lenses.

Alternating Bifocal Contact Lenses

• Alternating bifocal contacts have two distinct prescriptions. The top of the lens contains the prescription for distance, and the bottom of the lens has the prescription needed for looking at close objects. Since most alternating bifocals are rigid, gas-permeable lenses, the diameter is smaller than a soft lens, which enables the lens to stay in place even when the eye moves. Just like with bifocal eyeglasses, looking downward will allow the wearer to see through the lower part of the lens to focus on something close. Unlike bifocal lenses that contain two prescriptions with the same lens, multifocal lenses have a range of refractive powers.

Concentric Ring Designs

• Concentric ring designs are a type of bifocal contact known as simultaneous vision. This means that the eye will look through both corrective powers at the same time. This lens is made with a prescription in the center that is surrounded by one or more additional corrective rings with distinct prescriptions. The eye learns to select the prescription needed depending on the distance of the object on which the individual is focusing.

Aspheric Multifocal Contact Lenses

• Aspheric multifocal contact lenses also require simultaneous vision. Unlike lenses with a concentric ring design of separated prescriptions, the corrective powers of these lenses are blended. The powers on this lens are concentric; however, they are described as "progressive," since they are not distinct. This type of lens has become the most popular form of bifocal contact lenses.

Choosing a Bifocal Lens

• A visit with an eye care practitioner will help you learn which bifocal contact lens will work the best. Individual pupil size and prescription needs can be determining factors. The fitting process can be more time-consuming than with regular lenses, but most practitioners offer free trial lenses to determine which type works best.

Other Options

• Today's newer versions of bifocal contacts are much more effective than earlier versions. Some people still have difficulty adjusting to bifocal lenses, though, and may have greater success with a different approach. With monovision, you wear two different lenses--a lens to correct distance on one eye, and a lens with a correction for near vision on the other eye. Another technique known as modified monovision uses a multifocal lens on one eye and a single-vision lens in the other.